Did You Know?
The brightest star of the Eagle nebula HD 168076, is a binary star, with brightness magnitude of around 8.2, making it easy to spot with good binoculars near the constellation Serpens. Also, one can easily look at the nebula itself with a low-power telescope.
The Eagle nebula, also known as the Star Queen Nebula, designated as Messier 16 or M 16, is a star cluster and emission nebula, that can be found next to the constellation Serpens Cauda. It was first discovered by the Swiss astronomer P. Cheseaux, in 1746.
Located approximately 7000 light years away from earth, in the inner spiral of our galaxy, the Milky way, it is one of the most fascinating objects to observe in the night sky for both amateur and professional astronomers. The Eagle nebula is approximately 5.5 million years old and its size is a humongous 70 by 50 light years. It has an apparent brightness magnitude of 6.4, making it visible even through smaller telescopes.
How to Find the Eagle Nebula?
The best view of the Eagle nebula can be taken through images of the Hubble or Herschel Telescopes. However, to see the nebula for yourself, it is best seen with amateur telescopes in a low power. Besides looking towards the Serpens constellation, you can either find it by first locating the star Gamma Scuti, and looking westward to the nebula, or by looking northwards from the base of the Sagittarius constellation. In ideal conditions, you will also notice smaller nebulae, M17, M8, and M20 in the vicinity.
How Did it Form?
To know why it is called the Eagle nebula, look at the image above. You can see the triangular eagle's head towards the north at the top, while the wings extend from the sides towards the bottom of the image.
The nebula is made out of interstellar dust and hydrogen, oxygen, and sulfur gas, besides other elements. These gases are rapidly coming together to form new stars, which provide light that reflects off the entire area, making it easy for us to study this phenomenon. The specialty of the nebula is that despite not being the brightest, biggest, oldest, or the youngest nebula, it shows the various stars in different ages, and tells us how stars form and how they grow old and die. The temperature of the Eagle nebula's gases ranges from 10-40 Kelvin which goes into thousands of Kelvin when they turn into stars.
Scientists can study the neutral gas that is forming clumps to eventually become stars. They can also see how the radiation from these new stars is destroying the surrounding gas envelope from the inside, while ultraviolet rays slowly erode them from the outside through photoevaporation. Eventually, nearly all the gas of the nebula will be absorbed through nuclear fusion to form a star cluster with planets, that might hold life.
This is an infrared image of the Eagle Nebula from the Spitzer Space Telescope showing the cool star-forming gas and dust (blue-green), and the heated gas and dust caused by a supernova (red).
Pillars of Creation Within the Eagle Nebula
The Pillars of Creation are one of the most prominent features of the Eagle Nebula apart from the Stellar Spire. These huge pillars of gas and dust were given this name, due to the incredibly high number of new stars forming inside them. This phenomenon is occurring due to the high density and gravity of the dust and gas which causes them to contract and form thousands of stars.
It might seem impossible that these pillars can support so many stars, when each star is so huge. However, the size of these pillars is very deceptive due to the huge distance between them and Earth. The protruding tip at the top of the pillars alone, can contain our entire solar system. That should help us estimate exactly how big each of these pillars is. In fact, the tall pillar on the left of the image is more than 4 light years in length, i.e., approx. 23,462,784,000,000 miles long.
Recently, the European Space Agency's Herschel and XMM-Newton space telescopes took new pictures of the nebula and revealed the biggest surprise of all. The Pillars of Creation do not exist any more. In fact, they were probably destroyed around 6000 years ago by an exploding star/supernova. However, due to the immense distance of 7000 light years (approx. 41 quadrillion miles) between the nebula and Earth, the image taken by the Hubble telescope, actually shows us how the Pillars looked around 7000 years ago. It will take another millennium before astronomers on Earth can see the destruction that has taken place.
The Stellar Spire
This piece of the Eagle nebula looks like a statue of fairy with wings, that is standing on a pedestal. This huge structure is a 9.5 light years long spire of cold gas and dust, which come together to form Evaporating Gaseous Globules (EGGs), the source of stars. This is another region where the formation of new stars is rampant, and the ultraviolet light from these stars is visible in the image, which will slowly erode, and disappear in a few million years.
Simulacrum in the Eagle Nebula
When the Hubble telescope took pictures of the Eagle Nebula in 1995, the world was astounded by the exotic and strange nature of the universe. The pictures of these gaseous cosmic clouds, especially that of the Stellar Spire were especially interesting. When the picture was first shown on CNN, many of the viewers felt that they could see a face in the cloud. In fact, after the photo was color-adjusted, one could see a huge humanoid figure.
Scientists explained this away by saying, that similar to clouds in the Earth's atmosphere, the clouds in the nebula cause illusions or pareidolia, by taking various shapes. Such shapes are often visible across the universe in several nebulae, and other cosmic phenomena. The major difference between the clouds is that while the ones in the Earth's atmosphere create rains, those in the nebula form stars. An interesting note is that the Hubble telescope has taken many more pictures of this region since. However, a simulacrum is visible in most of them.
The Eagle nebula is important to us, as it gives us the answers to how most stars in our universe were formed. We can study this cosmic object for a few thousand years more. However, its estimated lifespan of 10-20,000 years means, that like everything else, the great eagle in the sky will be gone one day.